US3888425A - Method and apparatus for treatment of foliated metallic bearing materials - Google Patents

Abstract

The method of this invention includes the steps of heating and drying foliated metallic bearing materials; classifying the materials into selected size groups by permitting certain of the materials to pass through screens having preselected mesh sizes; selecting certain of the groups and blasting the same at substantially high velocity into a chamber to fracture the foliant matrix of the foliated metallic bearing material, by impinging the sides of the chamber; and separating metallic material from the foliant matrix. The apparatus for treating foliated metallic bearing materials includes the combination of a material reservoir, a blast gun assembly, and a fracture chamber assembly, the blast gun assembly being in communication with the reservoir and in communication with a remote source of substantially hot, dry air under pressure. The blast gun comprises a material chamber issuing into a blast chamber. The material is communicatingly connected to the reservoir by a conduit, and the blast chamber is connected to a remote source of air under pressure. The material is drawn from the reservoir into the material chamber in response to air under pressure in the blast chamber, and is carried by the air under pressure out of the blast chamber. The fracture chamber comprises a top wall, a bottom wall and a pair of opposing side walls, and is disposed distally from the gun assembly. The gun assembly is operable to discharge the material at an angle into one end of the fracture chamber assembly, wherein the fracture assembly is electrically conducting to ground potential. The blast gun assembly is electrically insulated from ground potential.

Description

United States Patent m1 Collins l l METHOD AND APPARATUS FOR TREATMENT OF FOLIATED METALLIC BEARING MATERIALS William 0. Collins, 2255 Foothill. Reno, Ney. 89502 [22] Filed: May 14 1973 [2]] Appl. No: 359,932

[76] Inventor:

Primary Emmim-rGran\ille Y. ('uster. Jr.

[57] ABSTRACT The method of this invention includes the steps of heating and drying foliated metallic bearing materials; classifying he materials into selected size groups by permitting certain of the materials to pass through screens ha ing preselected mesh sires: selecting cer- June 10, 1975 tain of the groups and blasting the same at substantially high velocity into a chamber to fracture the foliant matrix of the foliated metallic bearing material. by impinging the sides of the chamber; and separating metallic material from the foliant matrix.

The apparatus for treating foliated metallic bearing materials includes the combination of a material reservoir, a blast gun assembly and a fracture chamber assembly. the blast gun assembly being in communication with the reservoir and in communication with a remote source of substantially hot, dry air under pressure. The blast gun comprises a material chamber issuing into a blast chamber. The material is communicatingly connected to the reservoir by a conduit. and the blast chamber is connected to a remote source of air under pressure. The material is drawn from the reservoir into the material chamber in response to air under pressure in the blast chamber. and is carried by the air under pressure out of the blast chamber. The fracture chamber comprises a top wall. a bottom wall and a pair of opposing side walls. and is disposed distally from the gun assembly. The gun assembly is operable to discharge the material at an angle into one end of the fracture chamber assembly. wherein the fracture assembly is electrically conducting to ground potential. The blast gun assembly is electrically insulated from ground potential.

7 Claims. 4 Drawing Figures PATENTEDJUH 10 ms SHEET BAA/K RU/V n; METAL/C MATERIAL ASSEMBLY It i K II\ n" V METAL IC PRODUCT MA TERM L F RA CTURE FATENTEDJUN I 0 ms SHEU FIG. 3

METHOD AND APPARATUS FOR TREATMENT OF FOLIATED METALLIC BEARING MATERIALS FIELD OF INVENTION This invention relates to method and apparatus for treating foliated metallic bearing materials for recovery of precious metals.

BRIEF DESCRIPTION OF THE PRIOR ART Method and apparatus operable to economically separate foliant from metallic particles in foliated metallic bearing materials are generally unknown.

The foliated metallic bearing material generally comprises a metallic nucleus surrounded by a foliant. Suffree it to say here that commonly known fire or other assay methods are not usually effective to determine the presence or absence of metals because of the surface tension of the foliant or metal and the chemical character of the foliant.

The foliant ofthe metallic bearing material generally comprises a multiplicity of alkaline compound. crystallike particles made up chiefly ofthe basic alkaline earth family, and includes traces of ferro and titanic groups adhesively surrounding a metallic particle. Four types of foliants in oxide form have been classified with respect to date of formation and chemical ratio. Generally, all of the alkaline family have an extremely high activity within basic acids. However, the firm form of oxidation of the foliant material and the chemical com position of the material including traces of ferro-titanic oxides appear to limit such activity in acids. particularly with respect to the outermost surface of the native material in place. Hence, the foliant normally may not be economically disolved from about the metallic particle. Although, the alkaline oxide foliant found about such material has an average fracture point at about 3,2(J C, such extreme temperatures appear not to be conductive to recovering and separating the metallic material from the foliant material.

Accordingly, it is an object of the present invention to provide means by which a foliant may be separated from metallic particles economically.

Another object of this invention is to provide apparatus operable to negatively charge and to discharge foliated metallic bearing material to fracture the foliant entrapped metallic particles.

These and other objects shall become apparent from the description following, it being understood that modifications may be made without affecting the teachings of the invention here set out.

SUMMARY OF THE INVENTION Generally. the method of this invention includes the steps of heating and drying foliated metallic bearing materials; classifying the materials into selected size groups by permitting certain of the materials to pass through screens having preselected mesh sizes; selecting certain of the groups and blasting the same at substantially high velocity into a chamber to fracture the foliant matrix of the foliated metallic bearing material. by impinging the sides of the chamber; and separating metallic material from the foliant matrix.

The apparatus for treating foliated metallic bearing materials includes the combination of a material reservoir, a blast gun assembly. and a fracture chamber assembly. the blast gun assembly being in communication with the reservoir and in communication with a remote source of substantially hot. dry air under pressure. The blast gun comprises a material chamber issuing into a blast chamber. The material chamber is communicatingly connected to the reservoir by a conduit. and the blast chamber is connected to a remote source of air under pressure. The material is drawn from the reservoir into the material chamber in response to air under pressure in the blast chamber, and is carried by the air under pressure out of the blast chamber. The fracture chamber comprises a top wall, a bottom wall and a pair of opposing side walls; and is disposed distally from the gun assembly. The gun assembly is operable to discharge the material at an angle into one end of the fracture chamber assembly, wherein the fracture assembly is electrically conducting to ground potential. The blast gun assembly is electrically isulated from ground p0 tential.

A more thorough and comprehensive understanding may be had from the detailed description of the pre ferred embodiment when read in connection with the drawings forming a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a flow diagram of method taught by the present invention.

FIG. 2 is a fragmentary perspective view of the blast gun assembly and the fracture chamber assembly of the present invention showing to advantage the fracture chamber assembly mounted to grounding potential means.

FIG. 3 is a cross-sectional plan view of one type of a foliated metallic bearing material particle drawn to approximately one hundred times its actual size for illustrative purposes.

FIG. 4 is a cross-sectional plan view of a further known type of foliated metallic bearing material particles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and more particularly to the FIG. 1, the several steps of the process of treatment of foliated metallic bearing materials, as taught by the present invention. are shown, Native or bank run metallic material as found in its natural environment is put into a rotary kiln, the kiln being of the type and kind commonly known in the art. Foliated metallic bearing material is heated to approximately 250 C. in the kiln. The material is discharged from the kiln into a classifier. Material which may not pass through a commonly known size 10 mesh screen is conveyed to a waste or tailings deposit. since it has been found in practice that particles of this large size do not host metallic materials. Materials passing through ll) mesh screens and below are further classified into retained size groups ranging from It) to 40 mesh, 40 to mesh. 80 to I50 mesh, and below I50 mesh. Materials below mesh, retained upon a screen of that size, have been found to host nominal quantities of metals which may not be economically recovered by known pro cesses. Hence, such material is conveyed to the tailings deposit without further treatment. The several classified material groups of l0 to 40 mesh, 40 to 80 mesh. and 80 to 150 mesh are preferably each conveyed to separate material fracture assemblies of the type and character hereinafter later described.

The steps of the process required of a material fracture assembly means include negatively. electrically charging the dry. heated particles of foliated mctalic materials statically, blowing the particles with substantially dry air under pressure from a remote source against an electrically conducting plate. and statically discharging the particles by raising the potential of the particles to ground potential when contacting the plate. and, further. causing the particles to repetitively impinge the plate with sufficient force to fracture the foliant material surrounding such particles. Suffice it to say that particles tend to become statically negatively charged in the hot dry air of a rotary type kiln since the more positive protons tend to be dislodged from the particles as they cascade in the drum in response to rotation of the kiln. Some advantage has been noted when apparatus is electrically insulated to the impingement in the fracture chamber hereinafter later described. in practice, it has been found that the particles of retained classified material groups on the order of l to mesh, 40 to 80 mesh, and 80 to lSO mesh tend to become more uniformly charged separately in groups. than do particles of a conglomerate mass of foliated metallic bearing materials having all of the processable sizes above described.

Referring now to the FIGS. 3 and 4, a cross-section of each of two types of foliated metallic materials are shown in the respective drawings. Such materials have been found and identified in vast quantities in ancient trenches throughout the western portion of the United States. To better understand the processes and apparatus of this invention, an understanding of the nature of material may here be set out, because of the lack of data and knowledge concerning such material in the prior art. Although gold (A.,) shall herein become descriptive of the metallic substance. it is to be understood that such material does, in fact, host other precious metals. For convenience, the material of FIG. 3 is herein identified as Phase Ill metal; the metal of FIG. 4 being identified as Phase II metal, which identification is in concert with the identification classifications of free gold and Phase 1 gold hosted in a hard rock matrix in layers. Phase ll and Phase III metals differ only in that Phase ll metals include a matrix coating in addition to the foliant. and the metal particle is usually spherically shaped. That is to say that foliated metallic material generally comprises a metallic nucleus surrounded by a foliant. Suffice it to say here that commonly known fire or other assay methods are not usually effective to determine the presence or absence of metals because of the surface tension of the foliant or metal and the chemical character of the foliant.

The foliant of the metallic bearing material generally comprises a multiplicity of alkaline compound, crystallike particles made up chiefly ofthc basic alkaline earth family. and include traces of fcrro and titanic groups adhesively surrounding a metallic particle. In the drawings. the foliant crystaklike particles are identified by the letter F. while the metallic particle is identified All- Four types of foliants in oxide form have been classified with respect to date of formation and chemical ratio. Generally, all of the alkaline family have an extremely high activity within basic acids. However. the firm form of oxidation of the foliant material and the chemical composition of the foliant material including traces of fcrro-titanic oxides appear to severally limit such activity in acids. particularly with respect to the till outermost surface of the native material in place. Hence. the foliant normally may not be economically disolved from about the metallic particle. By experimentation, the alkaline oxide foliant found about such material has an average fracture point at about 3,200 C. However, such extreme temperatures appear not to be conducive to recovering and separating the metallic material from the foliant material. Experimentation also indicates that alkaline family foliant tends to be more negatively charged than the metallic particles to which they are attached. That is to say there appears to be an electrically static surface tension between the metallic particle and the foliant material. In practice, it has been found that. when the hot dry material is turbulatcd in a chamber. the material tends to become electrically a lesser potential; and that, when such particles contact an electrically grounded plate, the foliant ma terial tends to fracture or break about a line distally from the metallic particle. Such fracture line is gener ally shown in the drawing by the broken line. Additionally, surface tension between the foliant and metallic particles tends to be significantly reduced so that further, additional impingement of the particles on the plate tends to cause the foliant particles to be broken away from the metallic particles. With the outermost surface barrier broken away. the foliant tends to be more soluable, and may then be washed" from the metallic particle. Suffice it to say that the matrix coating about metallic particles of Phase Il material generally comprises alluvial matter which is soluable in water.

It should be pointed out that it has been found in practice that the natural material from its native environment has a specific gravity of 3.5; that the gold has a specific gravity of 17; that the foliant material has a specific gravity of 2; and that material fractured by the process above described has a resulting specific gravity of between 6 and 7.

Referring again to the flow diagram of the FIG. 1, fractured foliant metallic material is discharged from the material fracture assembly into a commonly known combination agitating-slurry classifier, preferably of the liquid (water! flotation type. in practice, it has been found that more violent agitation of the material tends to cause a greater proportion of foliant material and matrix material to be separated from the metallic material. [t is to be understood that any of a variety of independent separators and classififers may be used and employed to accomplish the steps of separating the metallic material and the foliant and matrix materials and in classifying the respective materials. The size classitied materials are then conveyed to a commonly known concentrator to separate the metallic materials from other materials.

Referring to the FIG. 2, the material fracture assembly of the present invention is generally shown and identified by the numeral 10. The material fracture as sembly includes a material reservoir 1], a blast gun assembly 12 in communication with the reservoir 11. and a fracture chamber 13 carried by a framework 14 mounted to a floor 15 in contact with original ground. The blast gun assembly 12 is distally disposed from the fracture chamber 13. The gun assembly 12 includes a turbulating material chamber 16 and a blast chamber 17, the blast chamber 17 being connected to a suitable remote source of air under pressure. Foliated metallic material tends to be drawn into the turbulating chamber 16 by vacuum pressure of the air passing through the blast chamber 17 of the gun assembly [2. ln practice it has been found that hot dry foliated metallic material tends to be negatively electrically charged by turbulent movement within the turbulating chamber l6. When the material is blasted from the blast chamber 17 into the fracture chamber 13 in response to air under pressure. its electrical potential tends to be raised to ground potential since the fracture chamber 13 is in communication with the ground through the floor 15 and the framework 14. It has also been found that the foliatcd material about the metallic material tends to fracture. and surface tension between the foliant material and the metallic material tends to be significantly reduced as hercinbeforc described in response to contact of the foliated metallic material with the fracturc chamber I3. It has further been found that initial engagement with the chamber 13 mcrcly causes fracture and release of surface tension regardless of force of the impinging material against the plates or walls of the fracture chamber 13. Therefore. it has been found to advantage to cause the material to repeatedly impinge the chamber [3 to break away foliant material from metallic material. For this reason the blast gun assembly I2 is preferably disposed at an angle to the fracture chamber 13. and has been found most effective when disposed at an angle less than 45.

The fracture chamber l3. shown to advantage in the FIG 2. preferably is provided with a substantially flat top wall plate 18. a pair of opposing sidewalls l9 and 19'. and an inverted. substantially shaped bottom wall which deflects thc foliant metallic material.

In operation. substantially dry. heated foliatcd metallic material is drawn from the reservoir I into the turbulating chamber 16 in response to air under pressure being introduced into the blast chamber 17 from a remote source. The material is then conducted into the blast chamber 17. and blown against the plate 18 of the fracture chamber 13. The material successively impinges the walls l8. l9. l9 and 20: and is ultimately discharged from the fracture chamber [3 at the end oppositc the blast gun assembly 12.

Having thus described in detail a preferred apparatus which embodies the concepts and principles of the invention and which accomplishes the various objects. purposes and aims thereof. it is to be appreciated and will be apparent to those slyillcd in the art that many physical changes could be made in the apparatus without altering the inventive concepts and principles embodied therein. Hence. it is intended that the scope of the invention be limited only to the extent indicated in the appended claims.

I claim:

I. The method of treating foliatcd metallic bearing materials comprising the steps of heating and drying foliated metallic bearing materials.

classifying said materials into selected size groups by permitting certain of the materials to pass through screens having several preselected mesh silcs of It) mesh to mesh.

selecting one of said sized groups and blasting said group at substantially high velocity into a chamber to fracture the foliant matrix of said foliatcd metallic bearing material. by impinging the sides of said chamber.

separating metallic material from said foliant matrix.

2. The method of claim 1 involving the steps of heating foliated metallic bearing material to approximately 250 C.

3. The method of claim 1 including the steps of agitating said material with substantially hot. dry air under pressure from a remote source when blasting said selected materials into said chamber to electrically statically negatively charge said selected materials before impinging said sides of said chamber. said chamber being electrically connected to conduct to ground potential.

4. In an apparatus for treating foliatcd metallic bearing materials the combination of a material reservoir. a blast gun assembly. and a fracture chamber assembly. said blast gun assembly being in communication with said reservoir and in communication with a remote source of substantially hot. dry air under pressure. said blast gun comprising a material chamber issuing into a blast chamber. said material chamber being communicatingly connected to said reservoir by a conduit. said blast chamber being connected to said remote source of air under pressure. said material being drawn from said reservoir into said material chamber in response to air under pressure in said blast chamber. said material being carried by said air under pressure out of said blast chamber. said fracture chamber comprising a top wall. a bottom wall and a pair of opposing side walls and being disposed distally from said gun assembly. said gun assembly being operable to discharge said material at an angle into one end of said fracture chamber assembly. said fracture assembly being mounted electrically conducting to ground potential. said blast gun assembly being electrically insulated from ground potential.

S. The apparatus ofclaim 4 in which said bottom wall of said fracture chamber is substantially \'-shaped.

6. The apparatus of claim 4 in which said blast chamber of said blast gun assembly is disposed at an angle to the top wall of said fracture chamber assembly.

7. The apparatus ofclaim 6 in which said blast chantber of said blast gun assembly is disposed at between approximately 30 and 45 to said top wall of said fracturc assembly.

Claims (7)

1. THE METHOD OF TREATING FOILATED METALLIC BEARING MATERIALS COMPRISING THE STEPS OF HEATING AND DRYING FOLIATED METALLIC BEARING MATERIALS, CLASSIFFYING SAID MATERIALS INTO SELECTED SIZE GROUPS BY PERMITTING CERTAIN OF THE MATERIALS TO PASS THROUGH SCREEN HAVING SEVERAL PRESELECTED MESH SIZES OF 10 MESH TO 150 MESH,

2. The method of claim 1 involving the steps of heating foliated metallic bearing material to approximately 250* C.

3. The method of claim 1 including the steps of agitating said material with substantially hot, dry air under pressure from a remote source when blasting said selected materials into said chamber to electrically statically negatively charge said selected materials before impinging said sides of said chamber, said chamber being electrically connected to conduct to ground potential.

4. In an apparatus for treating foliated metallic bearing materials the combination of a material reservoir, a blast gun assembly, and a fracture chamber assembly, said blast gun assembly being in communication with said reservoir and in communication with a remote source of substantially hot, dry air under pressure, said blast gun comprising a material chamber issuing into a blast chamber, said material chamber being communicatingly connected to said reservoir by a conduit, said blast chamber being connected to said remote source of air under pressure, said material being drawn from said reservoir into said material chamber in response to air under pressure in said blast chamber, said material being carried by said air under pressure out of said blast chamber, said fracture chamber comprising a top wall, a bottom wall and a pair of opposing side walls and being disposed distally from said gun assembly, said gun assembly being operable to discharge said material at an angle into one end of said fracture chamber assembly, said fracture assembly being mounted electrically conducting to ground potential, said blast gun assembly being electrically insulated from ground potential.

5. The apparatus of claim 4 in which said bottom wall of said fracture chamber is substantially V-shaped.

6. The apparatus of claim 4 in which said blast chamber of said blast gun assembly is disposed at an angle to the top wall of said fracture chamber assembly.

7. The apparatus of claim 6 in which said blast chamber of said blast gun assembly is disposed at between approximately 30* and 45* to said top wall of said fracture assembly.

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